The Leg
The Legs have heavy bones as well as the feet because they carry more weight. The feet are just like hand with tarsals, metatarsals and phalanges. There are only 2 bones in the foreleg these are the fibula and tibia. For running and jumping the thighbone (femur) has to be strong otherwise we would not be able to walk after completing these exercises. The pelvis is attached to the femur. In the pelvis is a pair of hip bones attached to the spine at the sacrum.
Muscles
The muscles of the body make the person look like what the person is for example the muscle in the chest or arms tell you how strong the person is. It makes the person come to life instead of just bones which can’t move with out muscles. Depending on what they do Muscles have different shapes and sizes.
The basic principle of the muscle is to contract or shorten just like the intercostals muscle in breathing. These are controlled by the nervous system in the brain. Muscle contract when fibres becomes smaller and thicker. A nerve fibre is in the middle of the muscle called the motor end- plate. Message are passed through this via muscle fibres this then taken to the brain. If it comes from the brain to the fibres, which are called myofibrils, then contraction takes place. Energy is got from ATP converted into ADP and then is turned back again so that the body has a store of energy.
The Muscle Structure contains Tissues but first it has muscle fibres they are mainly elongated cells. The tissues are fibrious connective tissue. Muscles Contract when thick myofilaments overlap thin myofilaments. When contraction takes place thick filaments slide between thin filaments. This action shortens muscle fibre. This makes greater contraction in the muscle as a whole. Contraction is slow sometimes in the muscle because of the mitochondria. There are more mitochondria in the body which is used in respiration to produce more energy, this means that they do not contract that much and they have increased blood flow in the capillaries because of the small diameter .
There are various types of Muscles
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Voluntary muscles they are attached to the bones, and works when you it is most need. A signal races to your brain along your nervous system. The voluntary muscles needed for the job are alerted. The voluntary muscles have other names. One of them has stripes across when you look at it under a microscope it’s name is striped muscle. The other is the skeletal muscle because you can see because it is bones are attached to it. Nearly 2/5th of our weight is voluntary muscle.
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Involuntary muscles are found in our internal organs. E.G. stomach and blood vessels to name a few. They work on their own and don’t need nerves to tell them to work. To keep blood flowing Contractions in the walls of the blood vessels help. Because it looks smooth under the microscope the involuntary muscles can also be called smooth muscle.
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Cardiac muscle is a mixture of an involuntary muscle and
Voluntary muscle because it is striped also works non-stop without tiring out by forming on walls of the heart.
Types of muscle contraction
Isotonic training means training that results in isotonic muscle contractions. This results in muscle contraction and a shortening of the muscle, resulting in movement. For example, lifting a weight with your arm. Most training we do is isotonic. This occurs when you use your muscles to successfully push or pull an object
Isometric training involves the muscle contracting, but it does not shorten, so there is no movement. For example, pushing against a wall is an example of this type of muscle contraction. This occurs when a muscle attempts to push or pull an immovable object.
Proprioceptors – These are the nerve endings that relay all the information about the musculoskeletal system to the central nervous system . Proprioceptors (also called mechanoreceptors) are the source of all proprioception: the perception of one's own body position and movement. They detect any changes in physical displacement (movement or position) and any changes in tension, or force, within the body. They are found in all nerve endings of the joints, muscles, and tendons. The proprioceptors related to stretching are located in the tendons and in the muscle fibers. The two kinds of muscle fibers are: intramural muscle fibers and extrafusal muscle fibers.
Extra fusil fibers are the ones that contain myofibrils and are what is usually meant when we talk about muscle fibers.
Intramural fibers are also called muscle spindles and lie parallel to the extrafusal fibers. The Muscle spindles, or stretch receptors are known as the primary proprioceptors in the muscle. There are other proprioceptor that comes into play during stretching and is located in the tendon near the end of the muscle fibre and is called the Golgi tendon organ. There is a third type of proprioceptor, called a pacinian corpuscle, is located close to the golgi tendon organ and is responsible for detecting changes in movement and pressure within the body. When the extrafusal fibers of a muscle lengthen, so do the intrafusal fibers (muscle spindles). The muscle spindle contains two different types of fibers (or stretch receptors) which are sensitive to the change in muscle length and the rate of change in muscle length. When muscles contract it places tension on the tendons where the Golgi tendon organ is located. The Golgi tendon organ is sensitive to the change in tension and the rate of change of the tension
The exercise sequence Preparation
Before the exercise we would firstly stretch. This so that muscles do not come out of place and that you don’t pull them. If this happens then you can’t carry on with the exercise. The bones joint together with the muscles are known as musculoskeletal system. This musculoskeletal system needs the muscle to be attached to the system other wise it will tear.
AIM
Our aim is to see how biomechanics can affect exercise in a small group.
Method
Our method was out of the AVCE Year 1 group 1 class a group would be formed usually of about 4to 5 students. This was completed. In my group we had 4 students who were. Kieran, James, Damilola and Chizoba. With my skills in team leading I was naturally put forward as the team leader and then gave jobs to other colleagues in the group. James became the performer of the exercise because he had experience in the usage of equipment regarding safety also, which exercise sequence he was comfortable with, that could give us the right results for our aim while Damilola helped gather some research on health and safety with Chizoba helping her until her main job arose as camerawoman. I also did my fair share in camera work along with Damilola.
My team leading skills were test when the first the sequence which was on weightlifting had been recorded the darkness was too much on the screen. I took the decision to re-film the sequence, this meant more changes could be made because not a lot of muscle could be seen so James was allowed to bring his friend who he trains with at the workhouse where we filmed the sequence to be involved as another performer. The productivity of this extra work made outcome rise by at least 50 %. Luck had changed after half term and production was getting slow. A little bit of luck was left over from earlier when Damilola left most of the research with me because she sadly departed from the course for personal reasons. The new might have been good with weight of about 30kg on both sides making a total of 60kg but it was no good on a video we needed it as pictures on paper to comment on.
Media resources were taking time with letting go and process the video. I could have done it at home but had problems with the broadband Internet and managed to fix it by upgrading to windows me but had to lose the usage of watching TV on the computer because no drivers available on the internet so I could not use the TV. I would have been nice because me comes provided with video editing software. This meant I found it harder to write. The group still pulled together though hard time but sharing ideas about the write up. Later images had finally been made and I was able to print the picture and talk more on the physics.
Safety
For safety the back need to be at a 450 angle when taking the exercise . Firstly we would need the weights on each side to be equal. The floor has to be even so that the bench does not wobble when you lie on it. Then you need a holder to place the weights on in case you need to rest. A lot of ATP is used in the exercise, which means that it is not good to spend too much time. Care must be Taken because you are supposed to take your time when doing the exercise and do not rush because you will not be able to make the muscles grow. You should take deep breaths. Do not push the bar up too high. The elbows should stay relaxed. . Shoulder bladed should remain on the backrest doing the bicep curl. . Do keep knees relaxed. Don’t rock back and forth when
When using the small weights, the arms kept straight. Lift the weights from the floor making sure that nothing is bent. After a while, Start to lift the weights as high as you can. This should be done slowly without putting too much strain on your self. Lift up and down slowly until you can feel that you have done enough. Keep your back straight in the normal position for the duration of the exercise. The weights should be put on the legs while the exercise is going on. Return the weights to the floor Slowly keeping the torso erect. Arms must be straight and head up with eyes looking forward with the chest being slightly forward.
The exercise sequence
You can see that in this sequence that this is a third class lever because the force is applied between the weight and the fulcrum. The other levers do not apply to this sequence. There are 3 types of levers. Here you Can see that James I flexing the elbow joint. Here the biceps are being contracted so that the forearm and hand are lifted.
1st levers have the pivot or fulcrum between the effort force and the load.
2nd type of levers has the load between the effort force and the fulcrum.
You could say that the 2nd law
The rate of change of momentum of an object is directly proportional to the resultant force acting on it.
The change in momentum takes place in the direction of the force. Or
F= mv-mu / t
This affects the sequence by the time it takes for the arm to move up and down because of the weight.
1st law
If there is no resultant force on an object,
- If it is not moving it will stay in the same place
If it is moving it keeps on moving at constant velocity (a constant speed in a straight line)
This affects the sequence if the person stop nothing moves until the person moves the object.
3rd Law
If object X exerts A force of on object Y, Then object Y exerts a force on object X.
To every reaction there is an equal and opposite reaction. This can because in this sequence because the weight will be heavy and exert a force which has to be equally matched by the person.
Force = Mass X acceleration You can see in this sequence that mass is 30 kg on two sides the acceleration is going to be very little change but the force need would be big.
From these the Change is evident. The muscles are being contracted more. The fibres are in the muscles are being pulled more in the top right of the picture. The bottom picture shows the triceps and bicep along with the extensor Being used heavily.
You also have
Speed = Distance x Time. This is not really a factor but can be measured just like all the others. Energy could be worked out so that you can say whether the person can improve by using up less energy.
Velocity =total displacements/time taken
Acceleration = Change in velocity / Time Taken
Momentum= mass x velocity
KE= ½ Mass x Velocity 2
GPE= mass x gravitational filed strength x change in height
If you look at the exercise sequence you can see the muscles used and how safely he is taking part in the exercise. The muscle are well toned .You can really see much picture of the arm on its own but that was because we did not make the stills our teachers when and converted the stills for us. The back is well toned as well. You can’t see the knee in the image but when he was doing exercise I saw he kept the knees bent.
A major Error was the fact the performers did not warm up enough. We did not have a close up shot and the stages were not that good. They should have known better because they were professional trainers.
Bibliography
Weight training for dummies
Brian Ward –The skeleton and movement
Dorling Kindersley Human Body Ted Smart